Id agree with big-all.
The bottom of a hollow core door is usally around 20 to 30mm in height so sometimes as much as three quarters of an inch can be cut off without recoring the bottom, however if you do wipe out the bottom rail completley then as big-all says you need to make sure that you clean out the inside well and push up the cardboard core to allow fitting of timber.
Then once you have done that make a new core to a snug fit on a bench saw if you have one and glue the inside edges of the door with a pva wood glue and insert core until flush with underside.
Next you should clamp the bottom of door preferably with a timber baton above and below either side of door to spread clamping forces.
After several hours depending on temperature undo clamps and clean up.
Vwalla a neatley cored door again.
With regards to latches these are situated approximately 1m from floor level.
Again as big-all says check the top and bottom of door and make sure you know which side the lock block is on.
If premdor they are usally marked lock indicating the correct side but as a safety measure tap the face of door on side stamped around half way down and make sure that it has a solid feel to it, i can recall two instances in my time where a door had been incorrectly stamped on the wrong side leaving nothing to screw handles to.
A lot of people think that a set of handles have to be in the centre line of a lock rail(middle rail)
This was mabe the case 100 years ago when the fitting of rim surface locks was the fashion but not anymore.
The middle rail on a modern door is usally quite low relative to the centre of door and the fitting of handles and latches to suit this height may result in the bottom screws of handles missing lock block completley.
With regard to fitting latches a 1inch hole is usally bored out then set latch into hole and drawaround it.
next carefully chisel out recess into door for face plate of latch then measure back from edge of door the backset of spindle hole in latch.
Mark door and bore through one side using an auger bit being carefull not to go right through opposite side, allow the point of drill to just pierce the other side of door face so you can see it then withdraw drill and bore from other side.
Very important here is to make sure when boring out door edge and faces is that you keep auger sguare to the face you are boring into.
Now finally with regards to trimming a door and knowing how much to trim off it really comes down to experience and need i say that the more often you do it the easier it is to judge.
But to stay on the safe side you should be lookin to trim off around 1mm at a time and rehanging, repeating the process until right.
Theres nothing worse than a door with a huge gap below.
Hope this is of some help to you...
